Drafting instrument



y 5, 1953 H. s. GILBERTSON 2,637,110

' DRAFTING INSTRUMENT Filed June 23, 1950 H9- 2 Fig. 3

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BY Mafia Patented May 5, 1953 UNITED STATES TENT OFFICE This inventionrelates to new and useful improvements in drafting instruments and theprimary object of the present invention is to provide a combinationruler, square, protractor and compass.

Another important object of the present invention is to provide adrafting instrument in the form of a right triangle whose hypotenuse isprovided with steps that are graduated in inches and fraction of inchesalong one edge of each step and the other edges of the steps beinggraduated in fractions of inches.

A further object of the present invention is to provide a draftinginstrument in the form of a right triangle so that the centering pointis at the point of intersection between the two sides and with a scaleon the face of the instrument showing degrees of angle approximately3-5-2- inches from the centering point so that the distance between each5 will be 1% of an inch and with holes in the instrument between the 5marks set at a secant to the circle of degrees to give strength to thematerial of which the instrument is made, such as plastic or othersuitable transparent material.

A still further aim of the present invention is to provide a draftinginstrument that is simple and practical in construction, small andcompact in structure, and which is adaptable for use in tracing maps anddesigns, and by placing instrument on original and obtaining variouspoints and transferring to copy, fairly accurate copies can be made.

Other objects and advantages reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming part hereof, wherein likenumerals refer to like parts throughout, and in which:

Figure 1 is a plan view of the present drafting instrument;

Figure 2 is an enlarged sectional view taken substantially on the planeof section line 2-2 of Figure 1; and

Figure 3 is an enlarged sectional view taken substantially on the planeof section line 3-3 of Figure 1.

Referring now to the drawings in detail, wherein for the purpose ofillustration, there is disclosed a preferred embodiment of the presentinvention, the numeral it) represents a flat sheet of material, such astransparent plastic, in the shape of a right triangle having first andsecond straight side edges i2 and it that are disposed perpendicular toeach other and which intersect at a centering point P.

1 Claim. (Cl. 33-404) The edges i2 and M are preferably six inches longand graduations G in inches and sixteenths of inches are provided on thesheet of material iii along the side edges I2 and it.

The hypotenuse of the right triangular sheet of material is providedwith steps or identical isosceles triangles it, It, 26, 22, 2t and 26whose bases are integrally formed with the hypotenuse of the righttriangular sheet of material. Each of the isosceles triangles isprovided with an edge that is disposed perpendicular to the side edge i2and which is one inch long and graduated as at I, in sixteenths of aninch.

The other side edges of the isosceles triangles are also one inch longand are disposed perpendicular to the side edge Hi. The side edges ofthe triangles It, I8, 25), 22 and 2 1 that are disposed perpendicular tothe side edge it are graduated into quarters of an inch, eighths of aninch, sixteenths of an inch, thirty-seconds of an inch and sixty-fourthsof an inch respectively as shown in Figure 1.

Pencil receiving apertures 28 are provided in the sheet of material it.These apertures lie on an imaginary straight line that intersects theside edges i2 and it so that the angles included between the straightline and the edges I2 and M will be 45. The apertures 28 are spacedapart an eighth of an inch with graduations H on the sheet of materialit disposed along the apertures 28.

Five arcuate lines are provided on the sheet of material it about thepoint P as a center. The arcuate lines are spaced equally apart and theoutermost arcuate line is spaced approximately 3st: from the centeringpoint P. Sets of radial lines L are provided on the sheet of material Itand intersect the arcuate lines. There are five lines in each set oflines to represent 5 and the distance between each 5 will be of an inch.Each set of lines is provided with a pencil receiving aperture A on eacharcuate line, there being five apertures A for each set of lines L or anaperture A for each degree with the degrees indicated in units of 5 asshown in Figure 1.

In view of the foregoing description taken in conjunction with theaccompanying drawings it is believed that a clear understanding of thedevice will be quite apparent to those skilled in this art. A moredetailed description is accordingly deemed unnecessary.

It is to be understood, however, that even though there is herein shownand described a preferred embodiment of the invention the same issusceptible to certain changes fully comprehended by the spirit of theinvention as herein described and the scope of the appended claim.Having described the invention, what is claimed as new is:

A drafting instrument comprising a flat sheet of material having firstand second straight o edges disposed perpendicular to each other and astepped edge whose risers are equal in length and which. risers.parallel the first edge of said sheet of material, each step of saidstepped edge including two relatively perpendicular edges of equallength, scales on the sheet of material along each edge of each step,additional similar scales on the sheet of material along the first andsecond edges, the scales along one edge of each step being similar inunit to the units of the scales along the first and second. edges. and.the scales along the other edges of the. steps.

being increments different from each other and also different from theunits along the first and second edges of the flat sheet of material.

HARRIS S. GILBERTS-ON;

References Cited in the file of this patent UNITED STATES PATENTS NumberNumber Name Date Wiley Oct. 14, 1947 Darling Oct. 18, 1887 Beckwith Aug.14, 1888 Powell May 31, 1910 Cha'pin n Apr- 24, 1928 FOREIGN PATENTSCountry Date Great Britain 1904 Switzerland Mar. 16, 1920 SwitzerlandJan. 16, 1947 Great Britain Feb. 18, 1932

